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Novel Reassortant Highly Pathogenic H5N2 Avian Influenza Viruses in Poultry in China  [PDF]
Guo Zhao, Xiaobing Gu, Xinlun Lu, Jinjin Pan, Zhiqiang Duan, Kunkun Zhao, Min Gu, Qingtao Liu, Liang He, Jian Chen, Shengqiang Ge, Yanhong Wang, Sujuan Chen, Xiaoquan Wang, Daxin Peng, Hongquan Wan, Xiufan Liu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0046183
Abstract: There has been multiple evidence that domestic poultry may act as a vessel for the generation of novel influenza A viruses. In this study, we have analyzed the evolution and pathogenicity of 4 H5N2 avian influenza viruses isolated from apparently healthy poultry from H5N1 virus endemic areas in China. Phylogenetic analysis revealed that two of these viruses, A/duck/Eastern China/1111/2011 (DK/EC/1111/11) and A/goose/Eastern China/1112/2011 (GS/EC/1112/11) were derived from reassortment events in which clade 2.3.4 highly pathogenic avian influenza (HPAI) H5N1 viruses acquired novel neuraminidase and nonstructural protein genes. Another two isolates, A/chicken/Hebei/1102/2010 (CK/HB/1102/10) and A/duck/Hebei/0908/2009 (DK/HB/0908/09), possess hemagglutinin (HA) gene belong to clade 7 H5 viruses and other genes from endemic H9N2 viruses, or from viruses of various subtypes of the natural gene pool. All of these H5N2 isolates bear characteristic sequences of HPAI virus at the cleavage site of HA, and animal experiments indicated that all of these viruses but DK/HB/0908/09 is highly pathogenic to chickens. In particular, DK/EC/1111/11 and GS/EC/1112/11 are also highly pathogenic to ducks and moderately pathogenic to mice. All of these 4 viruses were able to replicate in domestic ducks and mice without prior adaptation. The emergence of these novel H5N2 viruses adds more evidence for the active evolution of H5 viruses in Asia. The maintenance of the highly pathogenic phenotype of some of these viruses even after reassortment with a new NA subtypes, their ability to replicate and transmit in domestic poultry, and the pathogenicity in the mammalian mouse model, highlight the potential threat posed by these viruses to both veterinary and public health.
A rapid and sensitive real-time reverse transcription PCR for the pathotyping of South African H5N2 avian influenza viruses : research communication  [cached]
C. Abolnik
Onderstepoort Journal of Veterinary Research , 2010, DOI: 10.4102/ojvr.v75i4.110
Abstract: A Fluorescence resonance energy transfer (FRET) real-time reverse-transcription (rRT-PCR) assay was developed that distinguishes stains of South African and European highly pathogenic (HPAI) from low pathogenicity (LPAI) H5 avian influenza viruses in the absence of virus isolation, irrespective of the length of insertion at the hemagglutinin cleavage site (H0). The assay was used to pathotype H5-type viruses detected by rRT-PCR in ostrich tracheal swabs collected during the 2006 HPAI H5N2 outbreak in the Western Cape Province.
Evidence of Infection by H5N2 Highly Pathogenic Avian Influenza Viruses in Healthy Wild Waterfowl  [PDF]
Nicolas Gaidet equal contributor ,Giovanni Cattoli equal contributor,Saliha Hammoumi,Scott H. Newman,Ward Hagemeijer,John Y. Takekawa,Julien Cappelle,Tim Dodman,Tony Joannis,Patricia Gil,Isabella Monne,Alice Fusaro,Ilaria Capua,Shiiwuua Manu,Pierfrancesco Micheloni,Ulf Ottosson,John H. Mshelbwala,Juan Lubroth,Joseph Domenech,Fran?ois Monicat
PLOS Pathogens , 2008, DOI: 10.1371/journal.ppat.1000127
Abstract: The potential existence of a wild bird reservoir for highly pathogenic avian influenza (HPAI) has been recently questioned by the spread and the persisting circulation of H5N1 HPAI viruses, responsible for concurrent outbreaks in migratory and domestic birds over Asia, Europe, and Africa. During a large-scale surveillance programme over Eastern Europe, the Middle East, and Africa, we detected avian influenza viruses of H5N2 subtype with a highly pathogenic (HP) viral genotype in healthy birds of two wild waterfowl species sampled in Nigeria. We monitored the survival and regional movements of one of the infected birds through satellite telemetry, providing a rare evidence of a non-lethal natural infection by an HP viral genotype in wild birds. Phylogenetic analysis of the H5N2 viruses revealed close genetic relationships with H5 viruses of low pathogenicity circulating in Eurasian wild and domestic ducks. In addition, genetic analysis did not reveal known gallinaceous poultry adaptive mutations, suggesting that the emergence of HP strains could have taken place in either wild or domestic ducks or in non-gallinaceous species. The presence of coexisting but genetically distinguishable avian influenza viruses with an HP viral genotype in two cohabiting species of wild waterfowl, with evidence of non-lethal infection at least in one species and without evidence of prior extensive circulation of the virus in domestic poultry, suggest that some strains with a potential high pathogenicity for poultry could be maintained in a community of wild waterfowl.
Assessment of Poultry Products Supply and Market Prices During Avian Influenza Outbreak in Nigeria Evidence from Osun State
A.S. Oyekale,B.A. Shittu
Journal of Animal and Veterinary Advances , 2012, DOI: 10.3923/javaa.2012.3618.3622
Abstract: Avian Influenza outbreak was reported among Nigerian poultry farmers in 2006. The epidemic had serious implication for poultry farming development because several birds were destroyed and those that did not get infected lost market values due to reduction in demand. This study analyzed the impact of the epidemic on market prices of poultry products using survey data obtained from poultry product suppliers and consumers. The data were analyzed with simple descriptive statistics. Results show that 90% of the marketers reported drastic reduction in sale while 95% of the consumers reduced or totally abandon consumption of poultry products. Prices of poultry products also decline with turkey recording the highest reduction (5,000.00 per bird). It was recommended that stakeholders in the poultry industry should design consumer education and risk mitigation media programs for the public before any future outbreak in order to minimize future losses.
The performance of poultry egg farms after the 2006 avian influenza outbreak in north central, Nigeria
H.Y. Ibrahim,H.I. Ibrahim
Research Opinions in Animal & Veterinary Sciences , 2011,
Abstract: The study assessed the performance of the poultry egg farms after the outbreak of avian influenza in 2006 in the north central part of Nigeria. Seventeen poultry (17) farms were purposefully sampled for the study. The net farm income model, simple descriptive statistics and data envelopment analysis were used as analytical tools. The result shows that the poultry farms are making profits after the losses obtained due to the outbreak of avian influenza (AVI). The revenue from eggs and spent layers constitutes 52.3 % and 47.7 % of the total revenue respectively. The medium size farms are however making higher profits and are more technically efficient than the small size poultry farms. The technical efficiency scores for the small scale farms range from 0.23-1 with a mean of 0.51, while that for the medium size farms range from 0.38-1 with a mean of 0.73. The major constraints affecting poultry egg production include; fluctuations in egg production and high cost of feeds as well as vaccines. The study concluded that the performance of poultry egg farms in Nigeria can be enhanced through improvements in technical efficiency or an increase in scale of operation. The provision of subsidies to poultry farmers by the government was however recommended to ease the high production cost.
ISOLATION AND CHARACTERIZATION OF AVIAN INFLUENZA (H9N2) VIRUS FROM AN OUTBREAK AT POULTRY FARMS IN KARACHI  [cached]
Mohammad A. Muneer, Ali Mohammad Bahram, Zahid Munir, I. Hussain, K. Muhammad, Masood Rabbani, S. Akhtar, M. Aleem, Bakht Sultan1, Munir A. Tariq and K. Naeem2
Pakistan Veterinary Journal , 2001,
Abstract: Avian influenza virus (AIV) type H9N2 was isolated from poultry flocks which were suffering from acute respiratory illness in Karachi area. High haemagglutination inhibition (HI) titers against AIV virus type H9N2, ranging from 6.38 to 7.81, in the convalescent sera of birds were demonstrated. The infected flocks had mortality between 30 to 80 per cent. Those flocks also had considerable of HI titres against infectious bronchitis (IB) virus stains D274 and D1466, against which they were never vaccinated. It is believed that AI H9N2 virus in collaboration with IBV and some unidentified bacterial species caused high mortality in the infected flocks
Genes associated with pathogenicity of avian Escherichia coli (APEC) isolated from respiratory cases of poultry
Rocha, Ana C.G.P.;Rocha, Silvio L.S.;Lima-Rosa, Carlos A.V.;Souza, Guilherme F.;Moraes, Hamilton L.S.;Salle, Felipe O.;Moraes, Lucas B.;Salle, Carlos T.P.;
Pesquisa Veterinária Brasileira , 2008, DOI: 10.1590/S0100-736X2008000300009
Abstract: the virulence mechanisms of avian pathogenic escherichia coli (apec) have been continually studied and are believed to be multi-factorial. certain properties are primarily associated with virulent samples and have been identified in avian isolates. in this study a total of 61 e. coli, isolates from chicken flocks with respiratory symptomatology, were probed by polimerase chain reation (pcr) for the presence of genes responsible for the adhesion capacity, p fimbria (papc) e f11 fimbria (fela), colicin production (cvac), aerobactin presence (iuta), serum resistance (iss), temperature-sensitive hemagglutinin (tsh), and presence of k1 and k5 capsular antigens (kpsii). the iss gene was detected in 73,8%, tsh in 55,7%, iuta in 45,9%, fela in 39,3%, papc in 24,3%, cvac in 23% and kpsii in18%.
Sequence and phylogenetic analysis of H7N3 avian influenza viruses isolated from poultry in Pakistan 1995-2004
Muhammad A Abbas, Erica Spackman, David E Swayne, Zaheer Ahmed, Luciana Sarmento, Naila Siddique, Khalid Naeem, Abdul Hameed, Shafqat Rehmani
Virology Journal , 2010, DOI: 10.1186/1743-422x-7-137
Abstract: Phylogenetic analysis revealed that there were two introductions of H7 into Pakistan and one N3 introduction. Only one of the H7 introductions appears to have become established in poultry in Pakistan, while the other was isolated from two separate outbreaks 6 years apart. The data also shows that reassortment has occurred between H7N3 and H9N2 viruses in the field, likely during co-infection of poultry. Also, with the exception of these few reassortant isolates, all 8 genes in the predominant H7N3 virus lineage have evolved to be phylogenetically distinct.Although rigorous control measures have been implemented in commercial poultry in Pakistan, AIV is sporadically transmitted to poultry and among the different poultry industry compartments (broilers, broiler breeders, table egg layers). Since there is one primary H7 lineage which persists and that has reassorted with the H9N2 AIV in poultry, it suggests that there is a reservoir with some link commercial poultry. On a general level, this offers insight into the molecular ecology of AIV in poultry where the virus has persisted despite vaccination and biosecurity. This data also illustrates the importance of sustained surveillance for AIVs in poultry.Avian Influenza Viruses (AIV) are among the most prominent viruses affecting animal and public health. AIV infections have caused heavy economic losses to the poultry industry world-wide. Several, sporadic outbreaks of AIV of different subtypes have occurred in Pakistan since the mid-1990's [1-3] . The first highly pathogenic (HP) AIV outbreak was observed in Pakistan in December 1994 at Salgran, near the capital city of Islamabad. The disease was controlled within 4-5 months by mass vaccination with a vaccine prepared from a field isolate [4]. Then in November 1998 an outbreak that was later identified as H9N2 low pathogenicity (LP) AIV occurred in North West Frontier Province in otherwise healthy flocks that had not been vaccinated for AIV [1,3]. In 2000-2001, another
Quantifying Transmission of Highly Pathogenic and Low Pathogenicity H7N1 Avian Influenza in Turkeys  [PDF]
Roberto A. Saenz, Steve C. Essen, Sharon M. Brookes, Munir Iqbal, James L. N. Wood, Bryan T. Grenfell, John W. McCauley, Ian H. Brown, Julia R. Gog
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0045059
Abstract: Outbreaks of avian influenza in poultry can be devastating, yet many of the basic epidemiological parameters have not been accurately characterised. In 1999–2000 in Northern Italy, outbreaks of H7N1 low pathogenicity avian influenza virus (LPAI) were followed by the emergence of H7N1 highly pathogenic avian influenza virus (HPAI). This study investigates the transmission dynamics in turkeys of representative HPAI and LPAI H7N1 virus strains from this outbreak in an experimental setting, allowing direct comparison of the two strains. The fitted transmission rates for the two strains are similar: 2.04 (1.5–2.7) per day for HPAI, 2.01 (1.6–2.5) per day for LPAI. However, the mean infectious period is far shorter for HPAI (1.47 (1.3–1.7) days) than for LPAI (7.65 (7.0–8.3) days), due to the rapid death of infected turkeys. Hence the basic reproductive ratio, is significantly lower for HPAI (3.01 (2.2–4.0)) than for LPAI (15.3 (11.8–19.7)). The comparison of transmission rates and are critically important in relation to understanding how HPAI might emerge from LPAI. Two competing hypotheses for how transmission rates vary with population size are tested by fitting competing models to experiments with differing numbers of turkeys. A model with frequency-dependent transmission gives a significantly better fit to experimental data than density-dependent transmission. This has important implications for extrapolating experimental results from relatively small numbers of birds to the commercial poultry flock size, and for how control, including vaccination, might scale with flock size.
Evaluating Surveillance Strategies for the Early Detection of Low Pathogenicity Avian Influenza Infections  [PDF]
Arianna Comin, Arjan Stegeman, Stefano Marangon, Don Klinkenberg
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0035956
Abstract: In recent years, the early detection of low pathogenicity avian influenza (LPAI) viruses in poultry has become increasingly important, given their potential to mutate into highly pathogenic viruses. However, evaluations of LPAI surveillance have mainly focused on prevalence and not on the ability to act as an early warning system. We used a simulation model based on data from Italian LPAI epidemics in turkeys to evaluate different surveillance strategies in terms of their performance as early warning systems. The strategies differed in terms of sample size, sampling frequency, diagnostic tests, and whether or not active surveillance (i.e., routine laboratory testing of farms) was performed, and were also tested under different epidemiological scenarios. We compared surveillance strategies by simulating within-farm outbreaks. The output measures were the proportion of infected farms that are detected and the farm reproduction number (Rh). The first one provides an indication of the sensitivity of the surveillance system to detect within-farm infections, whereas Rh reflects the effectiveness of outbreak detection (i.e., if detection occurs soon enough to bring an epidemic under control). Increasing the sampling frequency was the most effective means of improving the timeliness of detection (i.e., it occurs earlier), whereas increasing the sample size increased the likelihood of detection. Surveillance was only effective in preventing an epidemic if actions were taken within two days of sampling. The strategies were not affected by the quality of the diagnostic test, although performing both serological and virological assays increased the sensitivity of active surveillance. Early detection of LPAI outbreaks in turkeys can be achieved by increasing the sampling frequency for active surveillance, though very frequent sampling may not be sustainable in the long term. We suggest that, when no LPAI virus is circulating yet and there is a low risk of virus introduction, a less frequent sampling approach might be admitted, provided that the surveillance is intensified as soon as the first outbreak is detected.
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